Duh, I mentioned it in my post.
If you had a product and call it Gorilla Glass and it got out that other vendors were providing the glass, not you, then your credibility as a company goes right out the window. No way would they do this.... As I said, Apple likely didn't want to get tied into one company for glass. If Corning can't keep up with the volume demand there would be a big product shortage. By using several vendors, you can get more product out the window. Many claimed early on that the iPhone 4 used GG, even iFixit and then they retracted it saying they didn't know.
Bottom line is that nobody really knows if it is or isn't. So, you can't come on here and claim it is anymore than I can say it isn't. All I can tell you is that my Samsung phone glass is much better than my iPhone.
Another interesting bit (and this could simply be the way it is designed) is that I had a GG phone glass break and you could no longer use it. With the iPhone you still can use it after the glass breaks.
Not sure why this is such a big deal anyway, the glass in all three of the phones I own is of good quality. Does it really make a difference if it is Corning or not?